Branched sulfosuccinamic acid emulsifiers for the production of particularly shear-stable despersions

ABSTRACT

New sulfosuccinamic acids and derivatives thereof corresonding to the following formula ##STR1## in which R represents a linear or branches, saturated or unsaturated alkyl group containing from 8 to 22 carbon atoms or a group of the formula R 4  --O--(CH 2 ) 3  --(R 4  =C 8  -C 22  alkyl), R 1  and R 2  represent hydrogen or --SO 3  M 1  and R 3  represents a group corresponding to the formula; ##STR2##  or to the forumla ##STR3## n is an integer of from 2 to 4 and M and M 1  independently of one another represent hydrogen or an alkali metal, an ammonium, C 1  -C 4  alkylammonium or C 2  -C 3  hydroxyalkylammonium group and their use as surfactants and emulsifiers in aqueous systems.

This invention relates to new sulfosuccinamic acids and derivativesthereof corresponding to the following formula. ##STR4## in which Rrepresents a linear or branched, saturated or unsaturated alkyl groupcontaining from 8 to 22 carbon atoms or a group of the formula R⁴--O--(CH₂)₃ --(R⁴ =C₈ -C₂₂ alkyl);

of the radicals

R¹ an R², one represents hydrogen and the other --SO₃ M¹ and

R³ represents a group corresponding to the formula ##STR5## or to theformula ##STR6## n is an integer of from 2 to 4 and M and M¹independently of one another represent hydrogen or an alkali metal, anammonium, C₁ -C₄ alkylammonium or C₂ -C₃ hydroxyalkylammonium group.

The invention also relates to the use of the compounds corresponding tothe formula I as surfactants and emulsifiers in aqueous systems.

Examples of R are the 2-ethylhexyl, decyl, dodecyl, tetradecyl,hexadecyl, octadecyl, octadecenyl, dodecyloxypropyl andoctadecyloxypropyl group.

Examples M and M¹ are sodium, potassium, ammonium, mono-, di- ortrimethylammonium, mono-, di- or triethylammonium, mono-, di- ortrihydroxyethylammonium and mono-or dihydroxypropylammonium.

The compounds of formula I may be obtained by methods known per se, forexample by reacting polyamides corresponding to the following formula##STR7## in which R and n are defined above and R⁵ represents hydrogenor --(CH₂)_(n) --NH₂, with maleic acid anhydride, the molar ratio of thesum of primary and secondary amino groups to maleic acid anhydride beingfrom 1:0.9 to 1:1.1 and preferably 1:1, and subsequently reacting thereaction products obtained with alkali or ammonium sulfites.

The quantity of alkali or ammonium sulfite used is selected in such away that from 0.95 to 1.05 moles of alkali or ammonium sulfite are usedper mole of maleic acid anhydride used. Amines corresponding to formulaII, in which R⁵ represents hydrogen, are described, for example, in J.Org. Chem., Vol. 15 (1950), pages 51 et seq. and J. Am. Chem. Soc., Vol67 (1945), page 1581. Amines corresponding to formula II, in which R⁵represents --(CH₂)_(n) --NH₂, may be obtained in accordance with U.S.Pat. No. 3,028,415 and U.S. Pat. No. 3,615,797.

Most of the known and commercially available emulsifiers consist of ahydrophobic hydrocarbon or alkylaryl radical containing a hydrophilicgroup, for example a sulfonate, sulfate, carboxylate or phosphonategroup. Units of ethylene oxide or propylene oxide may also be foundthrough suitable reactive groups onto a hydrophobic radical, wherebysurfactant properties are again obtained. Instead of one hydrophobicradical, two hydrophobic radicals may be attached to a hydrophilicgroup, as in the sulfosuccinic acid diesters. A list of variousemulsifiers and their manufacturers can be found, for example, in McCutcheon's Detergents and Emulsifiers 1971, 1972 and 1973 and alsopermanently in the journal Tenside Detergents.

Emulsifiers containing several hydrophilic groups on a hydrophobicradical are known and are described, for example, in U.S. Pat. Nos.2,206,249, 2,438,092, and 2,435,810.

Of the emulsifiers containing several hydrophilic anionic groups, onlythe tetrasodium salt corresponding to the following formula ##STR8##wherein R is defined as Octadecyl has acquired any real significance.This compound is said to be particularly suitable, for example, for theproduction of finely divided plastics dispersions (except forvinylacetate), in addition to which this emulsifier is said to beeminently suitable for improving the mechanical stability of thedispersions. It is also recommended for subsequent addition.

The new compounds corresponding to formula I are superior to thecompound known per se corresponding to formula III in their apparentlyunique property of improving shear stability and, at the same time, showother advantages. Thus, it is known that the compound corresponding toformula III clouds in acidic media, particularly at elevatedtemperature, and because of this also presents difficulties in thepolymerization of monomers of the type which are preferably polymerizedat acidic pH values.

The new compounds corresponding to formula I show an excellent effect inimproving the shear stability of plastics dispersions and are alsoeffective in acidic medium.

In addition, finely divided dispersions of particularly low viscosityare obtained which, in addition, do not foam on demonomerization.

The compounds according to the invention show excellent solubility inwater and have a good wetting power and a limited tendency towardsfoaming, particularly towards the formation of a stable fine-bubblefoam. Although the compounds according to the invention have specialproperties suitable for emulsion polymerization, they may also be usedfor the production of printing and rawing inks, water colors, cleaningpreparations of all kinds, for softening, fulling, mercerizing,preparation, as fabric softeners, for dyeing, for dry cleaning, as aspinning bath additive in viscose manufacture, for leather oils, for thecold fat-liquoring of leather, for dispersing lime soaps, as auxiliariesin the backing of carpets, for coating paper, for degreasing metalsurfaces as auxiliaries in flotation and petroleum production, asadditives for plant protection agents, in the photographic industry, fordisinfection, as indirect building materials and in mining (cf.Technische Anwendung der grenzflachen-ahtiven Verbindungen in ChemischeTaschenbucher No. 14, Verlag Chemie Weinheim, authos H. Bueren and H.Groβmann, 1971).

In principle, any technically important monomers which are known to besuitable for emulsion polymerization may be polymerized in the presenceof the compounds according to the invention in the mildly acidic toalkaline pH range. The following monomers are particularly mentioned:ethylene, 1,3-butadiene, isoprene, chloroprene, styrene, subsitutedstyrenes, such as 1-methylstyrene (in combination with other monomers),vinylchloride, vinylidene chloride, vinylacetate, vinylpropionate,vinylversatic ester, vinylisobutylether, acrylonitrile,methacrylonitrile, methylacrylate, ethylacrylate, n-butylacrylate,2-ethylhexylacrylate, methylmethacrylate, ethylmethacrylate,n-butylmethacrylate and mixtures thereof which may be assessed accordingto known copolymerization parameters. The glass transition temperaturesof such producible copolymers may be calculated again from knownequations. Plastics dispersions obtained may be film-forming ornonfilm-forming. In addition, acrylic acid, methacrylic acid,acrylamide, methacrylamide and vinyl monomers containing additionalfunctional groups may be copolymerized in known manner. Monomers such asthese are listed, for example, in F. Holscher "Dispersionensynthetischer Hochpolymerer", Part I, Springer Verlag Berlin Heidelberg,page 56.

Since the compounds according to the invention provide the plasticsdispersions prepared with them with excellent stability, they are alsorecommended as additives for the dispersion of various pigments inplastics dispersions. Thus, they may also be widely used in paintbinders, paper binders, leather binders, textile binders and moreespecially and preferably in fabric printing binders. It is alsopossible to provide dispersions prepared with standard anionic ornonionic emulsifiers with excellent shear stability by subsequentaddition of the emulsifiers according to the invention.

The polymerization in the presence of the compounds according to theinvention may be carried out by methods known per se in batches,semi-continuously or fully continuously. In principle, seed latices mayalso be used.

The compounds according to the invention used in quantities of from 0.5to at most 8%, based on monomer, lead to relatively finely dividedsuspensions or rather dispersions. Thus, it is possible to preparedispersions having mean particle diameters of from about 25 nm to 500 nmusing standard polymerization techniques. In the case of finely dividedbutadiene homopolymer and copolymer dispersions, low viscosities wereobserved, for example, even at solids contents of higher than 40%. Thecompounds according to the invention may be used with particularadvantage for preparing the finely divided components of bimodal systemsof the type which have recently been used to an increasing extent in theproduction of pigmented, highly filled spread-coating composition. Inthis case, the finely divided latices may be prepared with the compoundsaccording to the invention and subsequently mixed with coarser laticesof which the particle diameter is larger by a factor of from 1.5 to 4.

However, a latex may also be polymerized to large average particlesdiameters, the critical micelle concentration subsequently reached byaddition of a compound according to the invention and new particlesformed thereafter, so that bimodal systems may be formed in a one-shotprocess.

By virtue of their multifunctional hydrophilic groups, the emulsifiersaccording to the invention may be co-condensed with combinations whichreact, for example, with carboxyl groups. In that case, it is best touse the ammonium salts of the emulsifiers according to the inventioninstead of the sodium or potassium salts. The average latex-particlediameter in the following examples was determined by turbidimetricmethods. The specific turbidity K was measured and d was obtained from adiagram K-d. d means DAN (see DIN 53 206).

EXAMPLE 1

121 parts of N-dodecylpropanediyl diamine were dissolved in 80 parts oftoluene and 98 parts of maleic acid anhydride added at 50° to 60° C.After stirring for 30 minutes at a temperature of 50° to 60° C., thetoluene was distilled off under reduced pressure at 50° to 60° C. 221parts of the crude N-dodecyl-N,N'-propanediyl bis-maleamic acid ##STR9##were obtained.

Acid number: calculated: 255.7, found: 253.

100 parts of isopropanol and a solution of 120 parts of sodium sulfitein 400 parts of water were added to 210 parts of the product describedabove, followed by stirring at 80° to 90° C. until the titrimeticconcentration of sulfite had fallen below 0.02%.

830 parts of a clear, viscous aqueous solution of the sulfosuccinamicacid corresponding to the following formula were obtained: ##STR10##

EXAMPLE 2

98 parts of maleic acid anhydride were dissolved in 120 ml of toluene at50° to 60° C. and 163 parts of a technical tallow propylene diamine(amine equivalent 162) added to the resulting solution at the sametemperature. After stirring for 30 minutes at 50°-60° C., the toluenewas distilled off under reduced pressure, leaving as residue 261 partsof crude N-tallow alkyl-N,N'-propanediyl bismaleamic acid correspondingto the following formula ##STR11##

Acid number: calculated 214.6, found 220.

140 parts of isopropanol and a solution of 126 parts of sodium sulfitein 550 parts of water were added to the product obtained, followed bystirring for 4 hours at 80° to 90° C. Thereafter, the sulfiteconcentration amounted to 0.004%.

1077 parts of a clear, viscous aqueous solution of the sulfosuccinamicacid corresponding to the following formula ##STR12## were obtained.

The sulfosuccinamic acid corresponding to the following formula##STR13## is similarly obtained from N-dodecylethylene diamine byreaction with maleic acid anhydride and sodium sulfite.

EXAMPLE 3

53 parts of maleic acid anhydride were dissolved in toluene and asolution of 100 parts of N-(3-aminopropyl)-N-octadecyl-1,3-propanediyldiamine added to the resulting solution at 40° to 50° C. After stirringfor 2 hours at 40° to 50° C., the toluene was distilled off underreduced pressure, leaving as residue 152 parts of the crude bismaleamicacid corresponding to the following formula ##STR14##

Acid number: calculated 193, found 203.

Base-N: calculated at 2.4%, found 2.5%.

145 parts of the crude bis-maleamic acid were stirred for 6 hous at80°-90° C. with 190 parts of isopropanol and a solution of 64 parts ofsodium sulfite in 250 parts of water until the sulfite concentration hadfalled below 0.1%. A clear, viscous aqueous solution of thesulfosuccinamic acid corresponding to the following formula wasobtained: ##STR15##

EXAMPLE 4

The following components were introduced in the absence of air into a 40liter fine-steel autoclave equipped with a paddle stirrer, pressure andtemperature recorder and a pH meter:

    ______________________________________                                        Deionized water        14 170    g                                            Emulsifier, prepared in accordance with                                                              3 813     g                                            Example 1 in the form of a 10% aqueous                                        solution                                                                      Tert.-dodecylmercaptan 40        g                                            Potassium peroxodisulfate solution, 2.5%                                                             1 196     g                                            in water                                                                      Butadiene              12 788    g                                            ______________________________________                                    

All the components apart from the potassium persulfate solution areinitially introduced, the mixtur is heated to 60° C. and the potassiumpersulfate solution is then added all at once. The temperature(internal) is electronically controlled and is maintained to an accuracyof approx. 1 degree. After 6 hours, the temperature is increased to 62°C., after 12 hours from 62° C. to 65° C. and after 17 hours from 65° C.to 68° C.

Evaporation samples are taken at hourly intervals, the solids content ofthe latex is determined. Its surface tension is measured, its pH valueis determined and its particle size measured.

The following values are obtained (cf. Table I)

    ______________________________________                                                               Surface Tension                                                                          Average particle                            Time Solids   pH-value dyn/cm     diameter (nm)                               (hrs)                                                                              % b.w.   electr.  (stalagmometer)                                                                          turbidimetrically.                          ______________________________________                                        1    3.6      5.8      46.3       30                                          3    5.8      5.5      51.8       63                                          5    8.6      5.9      59.9       78                                          9    19.2     6.3      65.2       79                                          13   32.7     6.5      66.2       84                                          18   40.3      6.85    66.5       90                                          ______________________________________                                    

After polymerization, there is no coagulate in the reactor. The latexmay readily be free from residual monomers without any foaming. Thelatex is thinly liquid and is completely free from specks andmicrocoagulate.

EXAMPLE 5

The following constituents were introduced in the absence air into a 6liter fine-steel autoclave equipped with a paddle stirrer, pressure andtemperature recorder and pH-meter:

    ______________________________________                                        Deionized water         2 032    g                                            Emulsifier, prepared in accordance with                                                               546.6    g                                            Example 3 in the form of a 10% aqueous                                        solution                                                                      Tert.-dodecylmercaptan  5.7      g                                            Potassium peroxodisulfate solution, 2.5%                                                              59.5     g                                            in water                                                                      Potassium peroxodisulfate solution, 2.5%                                                              112      g                                            in water                                                                      Butadiene               1 823    g                                            ______________________________________                                    

All components apart from the activator solutions are initiallyintroduced and the mixture is heated to 60° C. at 150 r.p.m. When thetemperature of 60° C. is reached, the first activator solution (59.5 g)is introduced into the autoclave, the second activator solution beingintroduced over a period of 14 hours. Samples are taken at hourlyintervals. The course of the polymerization process is shown in thefollowing Table:

    ______________________________________                                        Time Temp.    Pressure  Solids   Particle diameter                            hrs  °C.                                                                             bar       content %                                                                              (nm)                                         ______________________________________                                        1    60       7.8       4        25                                           2    60       7.6       5.2      --                                           3    60       7.3       8.0      --                                           4    60       6.8       8.7      --                                           5    60       6.8       10.5     --                                           6    60       6.5       13.0     --                                           7    62       6.9       15.1     --                                           8    62       6.8       22.0     --                                           9    63       6.8       28.4     47                                           10   64       6.5       30.7     --                                           11   68       6.8       33.9     72                                           12   68       4.5       35.8     --                                           13   68       3.5       38.0     --                                           14   68       2.5       38.5     --                                           15   68       1.8       39.0     --                                           16   68       1.2       39.5     73                                           17   68       0.7       39.7     --                                           ______________________________________                                    

No coagulate was formed during the polymerization process and the latexwas free from specks and microcoagulate. The latex did not foam duringdemonomerization and the flowout time of the demonomerized latex fromthe orifice cup according to DIN 53 211 (100 cm dispersion, 20° C., 4 mmorifice) was approximately 30 seconds for a solids content of approx.41%.

EXAMPLE 6

The demonomerized polybutadiene latices prepared in accordance withExample 4 and 5 cannot be rubbed into coagulae balls between thefingertips simply by shearing. Shear stability was more accuratelyassessed by the following procedure:

500 g of latex were adjusted to pH 10 by addition of aqueous ammonia(NH₃) solution. The latex was then diluted to a solids content of 35% byweight.

80 g of this 35% latex were introduced into a 21 cm tall cylindricalmetal beaker (internal diameter 6 cm) provided externally with a coolingjacket. The metal beaker was embedded in a 13 cm wide, 13 cm long and 5cm deep fine steel block with a cylindrical recess and fixed therein byknurled-head screws. Arranged in uniform distribution inside the metalbeaker were 4 mm wide splashboards which extended from the bottom tobeyond the rim of the metal beaker and which were fixed to the wallsthereof by clamping rings, extending at right angles to the surface ofthose walls.

A stirring element consisting of a single disc 2 mm thick and 2 cm indiameter dipped into the latex inside the beaker. The disc was mountedon an approximately 8 cm long shaft which, from approx. 5 mm near thedisc, thickened in the upward direction and which was driven by ahigh-speed motor. The apparatus was equipped with an accurate revolutioncounter and the rotational speed could be adjusted exactly to a specificvalue, in this case 20,000 r.p.m. After a period predetermined by anelectronic stopwatch, in this case exactly 20 minutes, the motor wasswitched off. The apparatus as a whole was acomodated in asound-insulated box. After this shear stressing, the contents of themetal beaker were filtered through a narrow-mesh fine-steel sieve(square mesh width 50 micrometers), the coagulate remaining in the sievewas dried to constant weight and then reweighed.

In the case of the two alkalized latices, hardly any coagulate (approx.0.01 g) remained behind after this procedure. Accordingly, these laticesare extremely shearstable. When the pH value was reduced, for example byaddition of acetic acid, the stability of the dispersions decreaseconsiderably, becoming comparable with the usual emulsifiers in themildly acidic pH range.

The above-mentioned latices may be agglomerated by additions ofpolyvalent metal ions. They may also be agglomerated by mechanical shearstressing in the neutral to mildly acidified state.

EXAMPLE 7

This Example is intended to show that additions of the emulsifiersaccording to the invention to a dispersion prepared with anionicemulsifiers known per se considerably improve their shear stability. Itis also known that corresponding additions of anionic surfactants knowper se do not produce a comparable effect.

The model substance used was a 41% demonomerized polybuadiene latexhaving an average particle diameter of 110 nm. The latex was prepared bya semicontinuous feed process at 50° C. using in all 1.8% by weight ofan emulsifier mixture consisting of equal parts of potassium oleate andsodium lauryl sulfate, a redox system of a water-in-soluble organicperoxide (p-methanehydroperoxide), a water-soluble reducing agent(sodium formaldehyde sulfoxylate) and Fe(II) complexonate solution beingused as the initiator system.

85 g of this latex were weighed into a glass beaker, a solution of anemulsifier X in water (5% by weight), as specified in the followingTable, was added with stirring, a pH value of 10 was adjusted with 5% byweight ammonia solution and the mixture made up with water to 100 g. Themixture was then stirred slowly for about another 30 minutes.

The stirring stability was determined by the method described in Example6, 80 g of the approx. 35% latices being mechanically stressed for 20minutes at 20,000 r.p.m. at a constant temperature of 25° C. in theapparatus described in Example 6.

To enable the effectiveness of the various emulsifier additives to becompared,

(a) a smaller quantity (2.22×10⁻⁴ moles of emulsifier X/100 g ofpolymer),

(b) a larger quantity (8.57×10⁻³ moles of emulsifier X/100 g of polymer)

were added to the test latex before dilution. The effect of the smaller(a) and larger (b) additions is shown in the following Table.

    ______________________________________                                                             a %    b %                                                                    coagulate                                                                            coagulate                                         ______________________________________                                        Paraffin sulfonate mixture,                                                                          4.05     3.44                                          average chain length C.sub.14                                                 Sulfosuccinic acid dioctylester                                                                      3.49     1.16                                          Potassium laurate      3.39     1.42                                          Potassium oleate       3.69     1.13                                          C.sub.12 -C.sub.14 alkylbenzene sulfonate,                                                           3.15     1.21                                          Nasalts                                                                        ##STR16##             3.49     1.01                                           ##STR17##             1.95     0.18                                          (R = C.sub.18)                                                                (comparison)                                                                  Emulsifier of Example 1                                                                              1.71     0.14                                          (according to the invention)                                                  formula V                                                                     Emulsifier of Example 2                                                                              1.40     0.12                                          (according to the invention)                                                  formula VII                                                                   Emulsifier of Example 3                                                                              1.65     0.08                                          (according to the invention)                                                  formula X                                                                     ______________________________________                                    

We claim:
 1. Sulfosuccinamic acids and derivatives thereof correspondingto the following formula ##STR18## in which R represents a linear orbranched, saturated or unsaturated alkyl group containing from 8 to 22carbon atoms or a group of the formula R⁴ --O--(CH₂)₃ --, (R⁴ =C₈ -C₂alkyl);of the radicals R¹ and R², one represents hydrogen and the other--SO₃ M¹ and R³ represents a group corresponding to the formula##STR19## or to the formula ##STR20## n is an integer of from 2 to 4 andM and M¹ independently of one another represent hydrogen or an alkalimetal, an ammonium, C₁ -C₄ alkylammonium or C₂ -C₃ hydroxyalklammoniumgroup.
 2. Sulfosuccinamic acids and derivatives thereof according toclaim 1 whereinR is 2-ethylhexyl-, decyl-, dodecyl-, tetradecyl-,hexadecyl-, octadecyl-, dodecyloxypropyl- or octadecyl-oxypropyl.